Sealing nail for battery top cover and battery top cover structure

Abstract

The utility model relates to the field of battery sealing, particularly provides a sealing nail for a battery top cover and a battery top cover structure, and aims to solve the problem that the stress at the welding part of the conventional sealing nail cannot be effectively released. In order to achieve the purpose, the sealing nail for the battery top cover comprises a sealing nail main body which is used for extending into a liquid injection hole in the battery top cover to seal the liquid injection hole; the welding part is arranged on the side, away from the liquid injection hole, of the sealing nail body in the extending direction of the sealing nail body, the edge of the welding part protrudes out of the edge of the sealing nail body in the circumferential direction, and the welding part is used for being welded to the battery top cover; the groove penetrates through the welding part in the extending direction of the sealing nail body and then extends into the sealing nail body, and the groove is used for containing deformation generated after welding of the welding part. The groove of the sealing nail can relieve stress impact generated during welding.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of battery sealing, and specifically provides a sealing nail for battery top cover and battery top cover structure. BACKGROUND

[0002] At present, in the production process of the battery cell, the liquid injection hole on the battery top cover needs to be sealed. The original method is to combine the glue nail and the metal nail. The glue nail is first inserted into the liquid injection hole. The elastic deformation of the glue nail causes the glue nail to be extruded in the liquid injection hole, thereby sealing the liquid injection hole. After the glue nail is assembled, the metal sealing nail is installed above the glue nail. The metal sealing nail is welded on the metal cover plate by laser welding, so that the liquid injection hole is completely sealed. This sealing method needs to seal the liquid injection hole through two processes, which seriously affects the production efficiency. The burr generated by the glue nail structure cannot be removed by manual or secondary processing method, and only the glue nail production process can be improved. Moreover, too many parts of the battery cell increase the cost of the battery.

[0003] Therefore, the existing method uses an integrated metal sealing nail. The main nail body of the sealing nail is inserted into the liquid injection hole to seal the liquid injection hole to a certain extent. The welding part is arranged around the main nail body. The welding part is used for welding with the battery cover plate to completely seal the liquid injection hole. However, stress is generated during welding of the welding part. The stress cannot be effectively released, which may cause the welding part to protrude outward or crack and deform at the welding seam. In the prior art, a gap is left between the welding part and the battery cover plate. However, the space of the gap is limited, so the effect of releasing the welding stress of these methods is not good.

[0004] Correspondingly, there is a need in the art for a new technical solution to solve the above problems. UTILITY MODEL CONTENT

[0005] The utility model aims at solving the above technical problems, that is, solving the problem that the stress at the welding part of the existing sealing nail cannot be effectively released. For this purpose, the utility model provides a sealing nail for a battery top cover, which comprises: a sealing nail body, the sealing nail body is used for inserting into a liquid injection hole in the battery top cover to seal the liquid injection hole; a welding part, the welding part is arranged on the side of the sealing nail body away from the liquid injection hole along the extension direction of the sealing nail body, the edge of the welding part protrudes from the edge of the sealing nail body in the circumferential direction, and the welding part is used for welding with the battery top cover; and a groove, the groove extends into the sealing nail body after penetrating the welding part along the extension direction of the sealing nail body, and the groove is used for accommodating the deformation of the welding part after welding.

[0006] In the above specific embodiment of the sealing nail for the battery top cover, the sealing nail body is a cylinder, and the cross section of the groove is circular; the cross section of the welding part is annular.

[0007] In the specific embodiment of the sealing nail for the battery top cover, the outer diameter of the welding portion is not greater than 7.5 mm.

[0008] In the specific embodiment of the sealing nail for the battery top cover, the difference between the radius of the cross section of the outer peripheral wall of the sealing nail body and the radius of the groove is the side wall thickness of the sealing nail body, and the side wall thickness of the sealing nail body is less than or equal to 1 mm.

[0009] In the specific embodiment of the sealing nail for the battery top cover, the distance between the bottom surface of the groove and the bottom surface of the sealing nail body is the bottom thickness of the sealing nail body, and the bottom thickness of the sealing nail body is not less than 1.5 times the side wall thickness of the sealing nail body.

[0010] In the specific embodiment of the sealing nail for the battery top cover, the thickness of the welding portion is D2, and 0.3 mm≥D2≥0.2 mm.

[0011] In the specific embodiment of the sealing nail for the battery top cover, the upper edge of the outer edge of the welding portion is provided with a first chamfer; and / or the lower edge of the outer edge of the welding portion is provided with a second chamfer.

[0012] In the specific embodiment of the sealing nail for the battery top cover, the sealing nail is a metal sealing nail.

[0013] The utility model also provides a battery top cover structure, including any one of the above sealing nail, still include battery top cover, be provided with liquid injection hole and welding groove on battery top cover, when sealing nail body extends into liquid injection hole, welding portion is located in welding groove.

[0014] In the specific embodiment of the battery top cover structure, the battery top cover includes a metal plate and an insulating plate arranged in sequence along the extension direction of the sealing nail body, the liquid injection hole penetrates through the metal plate and the insulating plate, and the welding groove is arranged on the metal plate.

[0015] In the case of adopting the above technical scheme, the existence of the groove in the utility model provides additional space for the volume change of the metal after welding. Since the groove penetrates through the welding portion, when the liquid metal at the welding portion solidifies and causes volume increase, the welding area on the welding portion can deform towards the inside of the groove, thereby releasing the stress generated due to the volume change and effectively relieving the stress impact generated during welding. The existence of the groove can also guide the complex stress inside the welding joint to concentrate and release inside the groove, thereby reducing the stress level of the whole welding joint. BRIEF DESCRIPTION OF DRAWINGS

[0016] The preferred embodiments of the utility model will be described below with reference to the drawings, in which:

[0017] Figure 1is a structure schematic view of the sealing nail in the utility model;

[0018] Figure 2 is a top view of the sealing nail in the utility model;

[0019] Figure 3 is a section view of the sealing nail in the utility model from a certain perspective;

[0020] Figure 4 is a structure schematic view of the battery top cover in the utility model;

[0021] Figure 5 is a section view of the battery top cover in the utility model from a certain perspective;

[0022] Figure 6 is Figure 5 the enlarged view of A in the middle;

[0023] Figure 7 is a structure schematic view of the sealing nail and the liquid injection hole.

[0024] In the figure: 1, sealing nail main body, 2, welding part, 3, recess, 4, battery top cover, 41, metal plate, 42, insulating plate, 5, liquid injection hole, 51, first liquid injection hole, 52, second liquid injection hole, 6, welding groove, 7, first chamfer, 8, second chamfer. DETAILED DESCRIPTION

[0025] The preferred embodiments of the utility model are described below with reference to the drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the utility model, and are not used to limit the protection scope of the utility model. Those skilled in the art can adjust them as needed to adapt to specific application occasions.

[0026] It should be noted that in the description of the utility model, the terms "upper", "lower", "left", "right", "inner", "outer" and other terms indicating direction or positional relationship are based on the direction or positional relationship shown in the drawings, which is only for the convenience of description, and does not indicate or imply that the related devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model. In addition, the ordinal numbers "first", "second" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0027] In addition, it needs to be explained that, in the description of the utility model, unless another explicit provision and limitation, the term "mounting", "connection" should be broad sense understanding, for example, can be fixed connection, also can be detachable connection or integral connection, can be mechanical connection, also can be electrical connection, can be direct connection, also can be indirectly connected through intermediate medium. For the person skilled in the art, the specific meaning of the above-mentioned term in the utility model can be understood according to the specific circumstances.

[0028] Furthermore, in order to more clearly show the core technical scheme of the utility model, the description below omits the description of the known structure of the battery top cover, but this omission is only for the convenience of description and does not mean that the battery top cover can be without these structures.

[0029] As shown in Figures 1-3 The utility model discloses a sealing nail for battery top cover, including: sealing nail main part 1, sealing nail main part 1 extends along its own extension direction, and sealing nail main part 1 is used to extend into the liquid injection hole 5 in battery top cover 4;Welding portion 2, welding portion 2 is set in the side of sealing nail main part 1 away from liquid injection hole 5 along the extension direction of sealing nail main part 1, and the edge of welding portion 2 is protruding from the edge of sealing nail main part 1 along the circumference, welding portion 2 is used to be welded with battery top cover 4, and the projection of the outer edge of sealing nail main part 1 in the extension direction is within the projection of the outer edge of welding portion 2 in the extension direction;Groove 3, groove 3 extends to sealing nail main part 1 after penetrating welding portion 2 along the extension direction of sealing nail main part 1, but groove 3 does not penetrate sealing nail main part 1, and groove 3 is used to accommodate the deformation generated after welding of welding portion 2. Figure 3 In the figure, X direction represents the extension direction of sealing nail main part 1.

[0030] The density of metal in liquid state is generally lower than that in solid state, so when the liquid metal cools and solidifies into solid state, its volume will slightly increase. This volume change is particularly evident at the welded joint, because the welding area undergoes a rapid transition from liquid to solid state. If the welding area does not have enough space to accommodate this volume increase, the welding surface may appear raised or deformed. The welding protrusion not only affects the appearance quality of the welded joint, but also can cause the generation of internal stress. When the welding area is raised due to volume increase, it will exert pressure on the surrounding material. This pressure generates stress inside the welded joint, and if these stresses are not effectively released, they can cause cracking, deformation or failure of the welded joint.

[0031] In order to solve the problem that the stress of the existing sealing nail welding joint cannot be effectively released, a groove 3 is arranged on the sealing nail body 1 in the embodiment, and the groove 3 provides additional space for the volume change of the metal after welding. Since the groove 3 penetrates the welding part 2, when the liquid metal at the welding part 2 solidifies and causes volume expansion, the welding area on the welding part 2 can deform towards the inside of the groove 3, thereby releasing the stress caused by the volume change and effectively relieving the stress impact generated during welding.

[0032] The groove 3 can also serve as a stress release channel. During the welding process, due to temperature gradient and material property inhomogeneity, a complex stress field will be generated inside the welded joint. The presence of the groove 3 can guide these stresses to concentrate and release inside the groove 3, thereby reducing the overall stress level of the welded joint.

[0033] In the embodiment, the sealing nail body 1, the welding part 2 and the groove 3 are of an integrated structure. A single welding nail is used for sealing in the embodiment, and the assembly process of the sealing nail is as follows: the sealing nail body 1 of the sealing nail is inserted into the liquid injection hole 5, so that the sealing nail body 1 cooperates with the liquid injection hole 5 to play a sealing role and prevent the electrolyte from flowing out, and then the welding part 2 is welded with the battery top cover 4, so as to completely seal the liquid injection hole 5. In order to enable the sealing nail body 1 and the liquid injection hole 5 to cooperate with each other for sealing, the size of the sealing nail body 1 can be the same as that of the liquid injection hole 5.

[0034] Further, the material of the sealing nail is metal, and the metal sealing nail can be vibrated and polished to prevent metal chips from affecting assembly and to avoid burr problems.

[0035] Further, as shown in Figure 1 , since the liquid injection hole 5 is generally a circular hole, in order to better seal the liquid injection hole 5, the sealing nail body 1 is a cylinder. In order to better release stress, the cross section of the groove 3 is circular, and the axis of the groove 3 coincides with the axis of the sealing nail body 1; since the groove 3 extends into the sealing nail body 1 after penetrating the welding part 2, the cross section of the welding part 2 is annular, and the diameter of the groove 3 is equal to the inner diameter of the welding part 2.

[0036] Further, the groove 3 is arranged on the sealing nail to relieve stress impact, but if the groove 3 is not properly designed, it may affect the structural strength of the sealing nail, causing the sealing nail to be easily damaged and even affecting the sealing effect. In order to balance the stress impact relieving effect and ensure the stability and forming rate of the sealing nail, the size of each aspect of the sealing nail needs to be limited. As shown in Figure 2 , the inner diameter of the welding part 2 is R1, and the outer diameter of the welding part 2 is R2, and R2 is not greater than 7.5 mm. Because the metal sealing nail with too large size is prone to warping during assembly, and after warping, the subsequent laser welding will be poor, which cannot meet the sealing requirements.

[0037] Further, the difference between the radius of the cross section of the outer peripheral wall of the sealing nail body 1 and the radius of the groove 3 is the side wall thickness of the sealing nail body 1, and the side wall thickness of the sealing nail body 1 is less than or equal to 1 mm. When the sealing nail body 1 is assembled into the liquid injection hole 5, the thinner wall thickness can be deformed to facilitate the cooperation between the metal sealing nail and the liquid injection hole 5. In addition, the wall thickness less than or equal to 1 mm is also convenient for processing and manufacturing, and reduces the manufacturing cost of the sealing nail.

[0038] As shown in Figures 1-3 , the diameter of the cross section of the outer peripheral wall of the sealing nail body 1 is R3, and the inner diameter of the welding portion 2 is R1. Since the diameter of the groove 3 is equal to the inner diameter of the welding portion 2, the diameter of the groove 3 is also R1, that is, the side wall thickness of the sealing nail body 1 is (R3-R1) / 2, and (R3-R1) / 2≤1 mm.

[0039] In the embodiment, the diameter R3 of the cross section of the outer surface of the sealing nail body 1 can be appropriately increased, and the hole diameter of the liquid injection hole 5 is further increased to improve the liquid injection efficiency.

[0040] Further, the sealing nail can be produced by stamping, and the groove 3 can relieve welding stress. Those skilled in the art can increase the diameter or depth of the groove 3 according to the actual situation, but it is not the larger the better. If the size of the groove 3 is too large, the structure of the sealing nail will not be firm. In order to ensure the stability and forming rate of the sealing nail, the size of the sealing nail needs to be limited: the distance between the bottom surface of the groove 3 and the bottom surface of the sealing nail body 1 is the bottom thickness of the sealing nail body 1, and the bottom thickness of the sealing nail body 1 is not less than 1.5 times the side wall thickness of the sealing nail body 1. As shown in Figure 3 , the size of the sealing nail body 1 along its extension direction is the overall thickness D1 of the sealing nail, the size of the groove 3 along the extension direction of the sealing nail body 1 is the depth D3 of the groove 3, the bottom thickness of the sealing nail body 1 is equal to (D1-D3), and the side wall thickness of the sealing nail body 1 is (R3-R1) / 2. Therefore, (D1-D3)≥1.5×(R3-R1) / 2.

[0041] Further, the size of the welding portion 2 along the extension direction of the sealing nail body 1 is the thickness D2 of the welding portion 2, and 0.3 mm≥D2≥0.2 mm. The welding area between the welding portion 2 and the battery top cover 4 is small, and laser welding can be used for welding. If the thickness of the welding portion 2 is large, the welding energy required during welding is also large, which may generate large stress and affect the welding quality. In the embodiment, the thickness of the welding portion 2 is limited to avoid large welding stress during welding and improve the welding quality.

[0042] Further, as shown in Figure 3As shown, the upper edge of the outer edge of the welding portion 2 is provided with a first chamfer 7. After the welding portion 2 is welded on the battery top cover 4, the welding portion can be raised and protrude from the plane of the battery top cover 4, resulting in uneven surface, which not only affects the appearance of the battery, but also affects the subsequent processing. In the embodiment, the upper edge of the outer edge of the welding portion 2 is provided with a first chamfer 7, which reserves a part of the molten area. When the metal is melted during welding, it will gather in the gap, and the protrusion will occupy the space in this area. Therefore, the degree of protrusion of the protrusion from the surface of the battery top cover 4 can be reduced, the appearance can be improved, and the subsequent processing is facilitated.

[0043] It should be noted that, although Figure 3 The first chamfer 7 shown in the embodiment is a round chamfer, but this is not a limitation of the utility model. Those skilled in the art can use other forms of chamfers or even irregularly shaped recesses without deviating from the basic principles of the utility model. As long as a part of the molten area can be reserved for the metal to gather after melting, for example, an inclined chamfer of 45°, etc. These do not deviate from the principles of the utility model, and therefore fall within the protection scope of the utility model.

[0044] When the sealing nail cooperates with the battery top cover 4, metal chips can be left in the edge gap of the welding groove 6. The presence of the metal chips can cause the bottom surface of the welding portion 2 to not be in good contact with the surface of the welding groove 6, thereby affecting the overall sealing performance. In the embodiment, in order to solve the problem, a second chamfer 8 is arranged at the lower edge of the outer edge of the welding portion 2, leaving a part of space between the lower edge of the welding portion 2 and the edge of the welding groove 6. Even if there are residual metal chips, the metal chips are contained in the space and do not affect the cooperation of the sealing nail and the battery top cover 4, so as not to affect the overall sealing performance.

[0045] It should be noted that, although Figure 3 The second chamfer 8 shown in the embodiment is an inclined chamfer of 45°, but this is not a limitation of the utility model. Those skilled in the art can use other forms of chamfers or even irregularly shaped recesses without deviating from the basic principles of the utility model. As long as a part of the space can be reserved for the metal chips, for example, a round chamfer, etc. These do not deviate from the principles of the utility model, and therefore fall within the protection scope of the utility model. In order to reserve enough space, the inclined chamfer is preferably used as the second chamfer 8 in the embodiment.

[0046] The thickness of the welding portion 2 is D2, and 0.3mm≥D2≥0.2mm. Therefore, the size of the first chamfer 7 and the second chamfer 8 can be 0.1mm.

[0047] The utility model also provides a battery top cover structure. As Figures 4-5As shown, the battery top cover structure comprises the sealing nail of any one of the above, and further comprises a battery top cover 4, the battery top cover 4 is provided with a liquid injection hole 5 and a welding groove 6, the top of the liquid injection hole 5 is provided with the welding groove 6 for accommodating the welding part 2, the diameter of the welding groove 6 is greater than the outer diameter of the welding part 2, and when the sealing nail body 1 extends into the liquid injection hole 5, the welding part 2 is located in the welding groove 6. The diameter of the welding groove 6 is greater than the outer diameter of the welding part 2, so that a proper distance is maintained between the outer edge of the welding part 2 and the inner wall of the welding groove 6, facilitating the formation of a molten pool and being beneficial to improve the welding quality. The diameter of the welding groove 6 is R4, the outer diameter of the welding part 2 is R2, and R4-R2=0.2mm-1mm. In addition, the size of the welding groove 6 along the extension direction of the sealing nail body 1 is the height D4 of the welding groove 6, and the height D4 of the welding groove 6 should be equal to the thickness D2 of the welding part 2, so that the surface of the battery top cover 4 remains flat after assembly.

[0048] Further, as shown in the drawings, Figures 6-7 The battery top cover 4 comprises an outer metal plate 41 and an inner insulating plate 42, wherein the metal plate 41 can be an aluminum sheet, and the insulating plate 42 can be a plastic sheet. The liquid injection hole 5 penetrates through the metal plate 41 and the insulating plate 42, and the welding groove 6 is arranged on the metal plate 41.

[0049] The liquid injection hole 5 comprises a first liquid injection hole 51 and a second liquid injection hole 52 which are sequentially communicated, the first liquid injection hole 51 is arranged on the metal plate 41, and the second liquid injection hole 52 is arranged on the insulating plate 42. The diameter R6 of the second liquid injection hole 52 is greater than the diameter R5 of the first liquid injection hole 51, so that interference between the sealing nail body 1 and the insulating plate 42 during assembly of the sealing nail body 1 into the liquid injection hole 5 can be prevented, and the insulating plate 42 can be prevented from being pushed open.

[0050] The diameter R5 of the first liquid injection hole 51 is equal to the diameter R3 of the outer surface section of the sealing nail body 1, so that when the sealing nail body 1 extends into the liquid injection hole 51, the sealing nail body 1 can play a strong sealing role to prevent the electrolyte from flowing out.

[0051] The size of the battery top cover 4 along the extension direction of the sealing nail body 1 is the overall thickness D5 of the battery top cover 4, and the overall thickness D5 of the battery top cover 4 is greater than the overall thickness D1 of the sealing nail, so that the sealing nail can be prevented from contacting the battery cell inside the battery.

[0052] Those skilled in the art will understand that the combination of features of different embodiments means to be within the scope of the present application and to form different embodiments, although some embodiments described herein include certain features rather than others included in other embodiments. For example, in the claims of the present application, any one of the claimed embodiments can be used in any combination.

[0053] The technical scheme of the utility model has been described in combination with the preferred embodiments shown in the drawings, but the person skilled in the art can easily understand that the protection scope of the utility model is obviously not limited to these specific embodiments. The person skilled in the art can make equivalent changes or replacements to the related technical features without deviating from the principles of the utility model, and the technical schemes after the changes or replacements will all fall within the protection scope of the utility model.

Claims

1. A seal post for a battery top cover, characterized by, Comprising: a sealing nail body (1) for extending into a liquid injection hole (5) in a battery top cover (4) to seal the liquid injection hole (5); a welding portion (2) provided on a side of the sealing nail body (1) away from the liquid injection hole (5) along an extension direction of the sealing nail body (1), an edge of the welding portion (2) protruding in a circumferential direction from an edge of the sealing nail body (1), the welding portion (2) being used for welding with the battery top cover (4); a groove (3) extending into the sealing nail body (1) after penetrating through the welding portion (2) along the extension direction of the sealing nail body (1), the groove (3) being used for accommodating a deformation of the welding portion (2) after welding.

2. The sealing nail for a battery top cover according to claim 1, wherein: the sealing nail body (1) is a cylinder, and a cross section of the groove (3) is circular; a cross section of the welding portion (2) is circular ring-shaped.

3. The sealing nail for a battery top cover according to claim 2, wherein: an outer diameter of the welding portion (2) is not greater than 7.5 mm.

4. The sealing nail for a battery top cover according to claim 2, wherein: a difference between a radius of a cross section of an outer peripheral wall of the sealing nail body (1) and a radius of the groove (3) is a side wall thickness of the sealing nail body (1), and the side wall thickness of the sealing nail body (1) is less than or equal to 1 mm.

5. The sealing nail for a battery top cover according to claim 4, wherein: a distance between a bottom surface of the groove (3) and a bottom surface of the sealing nail body (1) is a bottom thickness of the sealing nail body (1), and the bottom thickness of the sealing nail body (1) is not less than 1.5 times of the side wall thickness of the sealing nail body (1).

6. The sealing nail for a battery top cover according to claim 1, wherein: a thickness of the welding portion (2) is D2, and 0.3 mm≥D2≥0.2 mm.

7. The sealing nail for a battery top cover according to claim 1, wherein: an upper edge of an outer edge of the welding portion (2) is provided with a first chamfer (7); and / or a lower edge of the outer edge of the welding portion (2) is provided with a second chamfer (8).

8. The sealing nail for a battery top cover according to claim 1, wherein: the sealing nail is a metal sealing nail.

9. A battery top cover structure, characterized by, The battery top cover structure according to any one of claims 1-8, further comprising a battery top cover (4) provided with the liquid injection hole (5) and a welding groove (6), and when the sealing nail body (1) extends into the liquid injection hole (5), the welding portion (2) is located in the welding groove (6).

10. The battery top cover structure according to claim 9, wherein: The battery top cover (4) comprises a metal plate (41) and an insulating plate (42) arranged in sequence along the extending direction of the sealing nail body (1), the injection hole (5) penetrates the metal plate (41) and the insulating plate (42), and the welding groove (6) is arranged on the metal plate (41).

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